High-performance information processing apparatuses and server devices that process and compute a considerable amount of information at high speed are desirably constructed such that many computation elements such as a plurality of central processing units (CPUs) and a plurality of graphics processing units (GPUs) (hereinafter referred to as CPUs) are connected together in parallel. The plurality of CPUs are mounted on a CPU board that is a circuit board unit having CPUs and memories mounted thereon and also having an input and output function and other control functions. In the CPU board, high-speed signal connection between the CPUs is achieved by circuit wiring (hereinafter referred to as a pattern). The information processing apparatus and the server device are hereinafter referred to as an information processing apparatus.
In general, the CPUs mounted in the information processing apparatus generate heat at high temperature. Therefore, a water-cooled information processing apparatus capable of cooling the CPUs more efficiently is becoming widespread. In the information processing apparatus, high-density mounting is desirable to mount a plurality of CPUs in a limited area. In this case, it is desirable that maintenance of the information processing apparatus may be carried out from the front of a rack that is a housing of the information processing apparatus so as to facilitate replacement of the CPU board having the CPUs mounted thereon. That is, the CPU board mounted in the information processing apparatus is removable from the information processing apparatus from the front of the rack.
FIG. 1 illustrates the structure of an information processing apparatus 10 of a comparative technology. A plurality of CPU board units 11 having a plurality of CPUs mounted thereon are mounted on a front side of a rack 12 in a height direction. The CPU board unit 11 includes a CPU board and a cover as a unit and is hereinafter referred to simply as a CPU board 11 while the illustration of the cover is omitted. The mounting of the plurality of CPU boards 11 on the front side of the rack 12 in the height direction may be referred to as mounting of the CPU boards 11 in a stacked state.
The CPU board 11 is inserted into the information processing apparatus 10 from the front of the rack 12 and is housed in the rack 12 while being guided by guide members 13 such as rails. The housed CPU board 11 is connected to a backplane 14 located in the rear of the rack 12 by a connector described later. The backplane 14 is hereinafter referred to as a BP 14. In the information processing apparatus 10 described in this comparative technology, two BPs 14 are arranged in the height direction of the information processing apparatus 10.
The BP 14 is fixed to the rack 12 with screws or the like. The plurality of CPU boards 11 are mounted in a stacked state in the rack 12 of the information processing apparatus 10. The CPU mounted on each of the plurality of CPU boards 11 is connected to the BP 14 by the connector and is connected to a CPU mounted on another CPU board 11 by a pattern formed on the BP 14. The CPU mounted on each of the plurality of CPU boards 11 is also connected to the other BP 14 of the same information processing apparatus 10 or to a BP 14 of another information processing apparatus 10 by a high-speed transmission cable (not illustrated) connected to the connector. The high-speed transmission cable is hereinafter referred to simply as a cable.
In general, the CPUs mounted on the CPU board 11 are cooled by cooling water. The cooling water is sent from an external cooling device (not illustrated) to a pipe 17 mounted in the rack 12 by using a hose. The cooling water that has entered the pipe 17 flows through one of two connection hoses 16 connected to the CPU board 11 and is supplied to the CPU board 11 via a water-cooling connector 18 (hereinafter referred to as a coupler 18). The coupler 18 is located on the CPU board 11 on the front side of the rack 12. The cooling water supplied to the CPU board 11 cools the CPUs through a cooling plate mounted on the CPU board 11. The cooling water turns into hot water and returns to the cooling device along an opposite route (through the coupler 18, the other connection hose 16, and the pipe 17). The cooling water is cooled and then reused.
FIG. 2 illustrates connection between the CPU board 11 and the BP 14 in the information processing apparatus 10. A plurality of CPUs 1 are mounted on the CPU board 11 and are connected together by a pattern 2 in the CPU board 11. A male or female high-speed transmission connector 3A (hereinafter referred to simply as a connector 3A) for connection to the BP 14 is mounted on the CPU board 11 on a rear side of the rack 12. A female or male connector 3 of an opposite type is mounted on the BP 14 side at a position that faces the connector 3A. Guide pins 4 and 4A (the guide pins 4 are located on the BP 14 side) are arranged on both sides of the connectors 3 and 3A, respectively, so as to securely fit the connectors 3 and 3A together. The connectors 3 and 3A are high-density connectors. Therefore, when the CPU board 11 is inserted into the information processing apparatus 10, the connector 3 on the BP 14 side is positionally fixed but the connector 3A on the CPU board 11 side and the connector 3 on the BP 14 side are securely fitted together through operations of the guide pins 4 and 4A. Thus, the CPU board 11 and the BP 14 are coupled together.
In a state in which the plurality of CPU boards 11 are coupled to the BP 14, each of the plurality of CPUs 1 mounted on each CPU board 11 and a CPU 1 mounted on another CPU board 11 are connected together by using a pattern in the BP 14. The CPU board 11 is connected to a CPU board 11 connected to the other BP 14 in the rack 12 or to a CPU board 11 mounted in a different information processing apparatus 10 by using cables 15 connected to cable connectors 8 attached to the BP 14 on the rear side of the rack 12. The connection between the cable connectors 8 attached to the BP 14 and the cables 15 is achieved by manually connecting each cable 15 to the corresponding cable connector 8.
The coupler 18 located at the distal end of the connection hose 16 through which the cooling water is exchanged between the pipe 17 and the CPU board 11 is manually connected to a coupler 18A mounted on the CPU board 11 on the front side of the rack 12. At the position where the CPUs 1 of the CPU board 11 are mounted, a cooling plate 9 is arranged so as to cool the CPUs 1. The inlet and the outlet of the cooling water in the cooling plate 9 are connected to the couplers 18A by conduits 19 arranged on the CPU board 11. The cooling water supplied from the pipe 17 to the CPU board 11 through one connection hose 16 and the couplers 18 and 18A cools the CPUs 1 by flowing through the cooling plate 9 from the conduit 19. The cooling water heated by flowing through the cooling plate 9 flows into the other couplers 18A and 18 through the conduit 19 and returns to the pipe 17 through the connection hose 16.
In recent years, the performance of the information processing apparatus has been increased so as to further increase the processing speed. It is desirable that the processing speed of a single CPU be increased and many CPUs be mounted and connected together.
The information processing apparatus of the comparative technology has the following problems.
(1) The fitting that uses the guide rails may be achieved by increasing the accuracy of the guide rails. When many high-density connectors are arranged on the back panel or when a plurality of high-density connectors are arranged on the substrate, the mere increase in the accuracy of the guide rails is not sufficient to achieve the fitting.
(2) The high-density mounting is desirable to mount more CPUs. Due to the manual connection of cables and couplers, it is desirable to secure a manual access or unlocking space to be used when the CPU board is inserted into and removed from the information processing apparatus, thereby hindering the high-density mounting.
The problems are described in more detail with reference to FIG. 3. As illustrated in FIG. 3, the connection hose 16 is manually connected to the coupler 18A located on the CPU board 11 on the front side of the rack 12. This structure causes a problem in that an access space indicated by the broken line is desired for insertion and removal of the connection hose 16 into and from the coupler 18A during maintenance work.
The cable 15 for connection to other information processing apparatuses is connected to the BP 14 on the rear side of the rack 12 by the cable connector 8. Therefore, the information processing apparatus 10 has a problem in that an access space indicated by the broken line is desired for insertion and removal of the cable 15 into and from the cable connector 8 during maintenance work.
The followings are reference documents.
[Document 1] Japanese National Publication of International Patent Application No. 2011-518395,
[Document 2] Japanese National Publication of International Patent Application No. 2013-533635,
[Document 3] Japanese Laid-open Patent Publication No. 2003-243095,
[Document 4] Japanese Laid-open Patent Publication No. 6-267622, and
[Document 5] Japanese Laid-open Patent Publication No. 4-332486.